Smart outlet

ABSTRACT

Various implementations described herein are directed to systems, apparatuses and methods for managing one or more loads connected to one or more power sources using one or more smart outlets. Apparatuses described herein may include smart outlets configured to communicate with one or more controllers and responsively connect and disconnect electrical loads connected thereto. Methods described herein may include signaling and/or controlling one or more loads from a group of loads to connect to or disconnect from one or more power sources.

CROSS-REFERENCE RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/690,588, filed Nov. 21, 2019, which is a continuation ofU.S. Non-Provisional patent application Ser. No. 15/812,279, filed Nov.14, 2017, now U.S. Pat. No. 10,587,118, which claims the prioritybenefit of U.S. Provisional Patent Application No. 62/422,273, filedNov. 15, 2016, entitled “Smart Outlet.” The patent applications listedin this paragraph are hereby incorporated by reference in theirentirety.

BACKGROUND

Some electrical systems include a group of loads and an input powersource that at times might not supply enough power to meet the totalpower demand by the group of loads. In another case, some electricalnetworks include a group of loads and more than one power source, and ifone or more power source(s) disconnect, there may be a risk that thepower that is supplied by the remaining power source(s) might not meetthe total power demand of the loads in the electrical network.

For example, a user's premises (e.g. a house or office) may be connectedto a main power grid as well as to an alternative power source, such asa backup storage device (such as a battery, flywheel, capacitor and/orsupercapacitor) or a renewable energy system. When there is an eventsuch as a power outage in the main grid, or any other emergencysituation which interrupts the power supplied by the main grid, theremay be a risk that the system may produce less power than the electricalappliances require. In such a system, it may be critical for certainappliances to remain powered. For example, in a house or office it maybe critical that a life support system, refrigerator, or securitycameras will continue working during such an event, while a treadmill, atelevision or a microwave may be disconnected to save power depending onthe user's priorities.

Accordingly, there may be a need for a system of smart prioritized powerdistribution amongst several loads.

SUMMARY

The following summary is for illustrative purposes only, and is notintended to limit or constrain the detailed description.

Features disclosed herein may include methods for disconnecting loadsaccording to priority labels at times where there may be less poweravailable than the total power associated by the loads (e.g. required bythe loads), or when there may be other considerations that need to betaken into account such as energetic or financial limitations.

Instead of using the term “subscriber's premises,” description offeatures may use examples such as a house or an office. In all casesthese examples are to be non-limiting, and they may be replaced with anyother premises.

Features disclosed herein may employ methods and apparatuses forswitching of electrical loads according to one or more of prioritylabels, available power, available energy, cost and/or power demand.

Illustrative features may include use of a “Smart Outlet,” e.g. anelectrical outlet with communication and/or control capabilities,configured to connect and disconnect loads from the electrical powersupply provided by the electrical outlet.

In illustrative electrical systems, a group of electrical loads may beelectrically connected or connectable to one or more electrical powersources. For example, a home comprising dozens of electrical appliancesmay be connected or connectable to an electrical grid in addition to oneor more alternative power sources (e.g. photovoltaic source(s), storagedevice(s), battery(ies), windmill(s), fuel cell(s), flywheel(s), etc.).The alternative power sources may serve as auxiliary power supplies thatreduce the power consumed form the electrical grid. Additionally, oralternatively, the alternative power sources may serve as backupsupplies that ensure continuous supply of power to the electrical loadsduring a grid outage.

Photovoltaic (PV) sources and PV generators referred to within one ormore features may be PV cell(s), PV string(s), PV substring(s), PVpanel(s), PV array(s) of panels and/or PV shingles.

Power converters and/or converters referred to within one or morefeatures may be inverters, microinverters, a charge-pump converter,AC/DC converters and/or DC/DC converters.

According to features of the disclosure herein, the power that may begenerated from the input power sources may be less than the power thatmay be needed to operate the electrical loads that may be connected tothe electrical network. In this case, there might be a risk that some orall of the loads might not work properly. Disconnecting one or more ofthe loads from the electrical network according to priority labels mayreduce the total power demand from the loads, and allow the rest of theloads that may be still connected to the electrical network to receiveenough power to work properly.

According to features of the disclosure herein, the power generated bythe power sources may be sufficient to support the power needed tooperate all the electrical loads that may be connected to the electricalnetwork for a limited time. In this case, there might be a risk thatafter this limited time, one or more of the loads might not workproperly. Disconnecting one or more of the loads from the electricalnetwork may reduce the total power demanded by loads, thereby reducingthe rate of energy drawn from the power sources and prolonging theperiod of time for which the power sources may properly provide power tocritical loads.

According to features of the disclosure herein, the power generated bythe power sources may be sufficient to support the power needed tooperate all or most of the electrical loads that may be connected to theelectrical network, but the price of energy may be high for a certainperiod of time. For example, some utility grids feature dynamic pricingmodels, in which the cost of drawing electricity from the grid may bevariable over the course of the day. In this case, one may wish toreduce the power consumed from the power sources until the price isreduced.

Disconnecting some of the loads from the electrical network may reducethe total power demand from the loads, and perhaps reduce the cost ofpower during the period of time when energy has a high price.

Some features may be subject to some or all of the limitations mentionedabove, i.e. insufficient power, insufficient energy and/or high cost.

According to features of the disclosure herein, the decision of whichloads to connect to the electrical network and which loads to disconnectmay be made according to priority labels that may be assigned to eachload or group of loads. According to features of the disclosure herein,high-priority loads may be disconnected if the loads with lower prioritymay be already disconnected.

According to features of the disclosure herein, a user may manually setthe priority of each load or group of loads according to userpreference, and according to features of the disclosure herein, settingpriorities may be an automatic process carried out by a computer thatmay be programmed to set the priorities.

For example, power sources may supply electrical power to loads, and incase of insufficient power generation (i.e. when the loads may requiremore power than that may be produced by the power sources), some loadsmay be disconnected in order to reduce the power required by the loadsto ensure that at least some of the loads may work properly.

According to features of the disclosure herein, communication betweendifferent elements of the electrical network may be supported to allowthe sharing of information in order to optimize the management of theloads. A system management unit may communicate with a switching circuitto control the connecting and disconnecting of loads. According tofeatures of the disclosure herein, the system management unit maycommunicate directly with the loads for updating priorities.Communication may be carried out via numerous methods (e.g. Power LineCommunication, or other wired or wireless communication methods).

Power sources referred to within one or more of the features may includemain power grids, micro power grids, batteries, fuel cells, renewableenergy sources (such as photo voltaic systems, wind turbines, waterturbines etc.), and any other system with a purpose or an outcome ofgenerating electrical power. In almost all cases it may be possible toreplace one source with another. Therefore, though one type of powersource may be given as an example in each feature, the feature mayinclude each of these aforementioned power sources.

Electrical connections referred to within one or more of the featuresmay vary among outlets, inlets, plugs, sockets, wires, transformers orany other device with the purpose of enabling the flow of electricalpower through it.

Switches referred to within one or more of the features may be devicesthat have two or more terminals and may allow or block electricalcurrent flowing from one terminal to the others. In the case of a switchwith only two terminals, turning a switch “on” results in the switchallowing electrical current to flow from one terminal to the other, andturning a switch “off” results in the switch blocking the flow ofelectrical current from one terminal to the other. It is understood thatone of ordinary skill in the art may slightly modify methods disclosedherein to reverse this definition. Such modified methods are within thescope of the features disclosed herein.

Switching circuits and control thereof may be designed for rapid andefficient switching of loads between power sources according toillustrative features. Some features may include switching circuitscomprising one or more parallel-connected switching devices. Forexample, an illustrative single-pole-multi-throw (SPMT) switch may beimplemented using multiple parallel-connected branches. Each branch mayinclude a transistor (e.g. MOSFET—Metal Oxide Semiconductor Field EffectTransistor, or IGBT—Insulated Gate Bipolar Transistor) in parallel to anelectromechanical relay. The relay may provide low steady-stateresistance and the transistor may provide a fast switching response andlimit the voltage drop over the relay during switching.

In some illustrative features, electrical distribution boards mayinclude one or more integrated switching circuits for connecting one ormore subsidiary circuits of the distribution board to a selected powersource of one or more power sources. According to features of thedisclosure herein, distribution boards may be originally designedincluding switching circuits for connecting subsidiary circuits todifferent power sources. According to features of the disclosure herein,a switching circuit may be retrofit to an existing distribution board toadd a functionality of switching loads.

To facilitate smooth switching of a load from one power source toanother, features may include synchronizing power source voltages toavoid providing a load with a supply voltage signal featuringdiscontinuities. For example, according to features of the disclosureherein, a power converter converting direct current (DC) power from a DCpower source to alternating current (AC) power may be synchronized withan electrical grid and configured to output an AC voltage of the samemagnitude, frequency and phase as the grid.

Further features include user interfaces for monitoring load division insome power systems. A system owner or operator may be able to view alist of system loads, power sources, switches and priorities with amapping between loads, switches, priorities and power sources. Accordingto features of the disclosure herein, the list may be a graphical userinterface (GUI) viewable on a computing device, such as a computermonitor, tablet, smart-television, smartphone, or the like. According tofeatures of the disclosure herein, the system operator may be able tomanually set the priority of switches through the GUI (e.g. by pressingbuttons or touching a touchscreen).

As noted above, this Summary is merely a summary of some of the featuresdescribed herein and is provided to introduce a selection of concepts ina simplified form that are further described below in the DetailedDescription. The Summary is not exhaustive, is not intended to identifykey features or essential features of the claimed subject matter and isnot to be a limitation on the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood with regard to the followingdescription, claims, and drawings. The present disclosure is illustratedby way of example, and not limited by, the accompanying figures in whichlike numerals indicate similar elements.

FIG. 1 illustrates an electric circuit with a switch that depends onpriority according to illustrative features.

FIG. 2 illustrates an electrical network according to illustrativefeatures.

FIG. 3 a illustrates a centralized control method according toillustrative features.

FIG. 3 b illustrates a decentralized control method according toillustrative features.

FIG. 4 illustrates a combination of a centralized control method and adecentralized control method according to illustrative features.

FIG. 5 illustrates a Smart Outlet according to illustrative features.

FIG. 5 a illustrates a Rotary Switch according to illustrative features.

FIG. 6 illustrates a connection of a house to power sources via adistribution board according to illustrative features.

FIG. 7 illustrates a smart circuit breaker according to illustrativefeatures.

FIG. 8 illustrates an electrical network according to illustrativefeatures.

FIG. 9 a illustrates a method for switching according to illustrativefeatures.

FIG. 9 b illustrates a method for switching according to according toillustrative features.

FIG. 10 illustrates a method for operating a broadcast signal accordingto illustrative features.

FIG. 11 illustrates a method for operating a broadcast signal accordingto illustrative features.

FIG. 12 illustrates a method for switching according to illustrativefeatures.

FIG. 13 illustrates communication between controllers according toillustrative features.

FIG. 14 illustrates communication between controllers according toillustrative features.

FIG. 15 illustrates communication between controllers according toillustrative features.

FIG. 16 illustrates an electrical system according to illustrativefeatures.

FIG. 17 illustrates a scheme for a dual system according to illustrativefeatures.

FIG. 18 illustrates a scheme for a dual system according to illustrativefeatures.

FIG. 19 illustrates a dual smart outlet according to illustrativefeatures.

FIG. 20 a illustrates an example for a page in a GUI according toillustrative features.

FIG. 20 b illustrates an example for a page in a GUI according toillustrative features.

FIGS. 21 a and 21 b illustrate examples of designs of a dual smartoutlet according to illustrative features.

FIG. 22 illustrates an example for a design of a dual smart outletaccording to illustrative features.

DETAILED DESCRIPTION

In the following description of various illustrative features, referenceis made to the accompanying drawings, which form a part hereof, and inwhich is shown, by way of illustration, various features in whichaspects of the disclosure may be practiced. It is to be understood thatother features may be utilized and structural and functionalmodifications may be made, without departing from the scope of thepresent disclosure.

For clarity and reduction of visual noise, many of the figures disclosedherein feature single-line electrical connections where multi-lineconnections would normally be used. It is to be understood that somesingle-line electrical connections would be implemented, according tofeatures of the disclosure herein, as two lines (e.g. a direct-current(DC) positive line and a direct-current (DC) negative/ground line) orthree or more lines (e.g. some three-phase alternating-current (AC)systems feature three lines, and some include a fourth, “neutral” line).

Electrical power may be defined as the amount of energy consumed orproduced per time unit. The integral of the electrical power supplied bya power source over a specific time interval may be defined as theenergy supplied by the power source in that time interval. Someelectrical power sources may have limited power, meaning they have alimit on the rate of energy they may supply. Other electrical powersources may have limited energy, meaning they might not supply power forinfinite time. Some power sources may have a combination of bothlimitations.

According to features of the disclosure herein, the main power grid maybe a smart grid, supporting time-based pricing programs or dynamicpricing programs that use real-time or day-ahead hourly electricityrates. For example the price of watt-hour may be broadcasted over thegrid, and a system-control device may react accordingly by reducing thepower demand of the local electrical network when the price may be highor over a threshold price. One possible way to implement this may be byassuming there may be information received from the main power gridregarding the current price of watt-hour. A threshold may be set for theprice of watt-hour. When above said threshold, the system-control devicereacts as described for a power outage, achieving a smaller powerdemand. The threshold may change dynamically over time according to userpreference.

According to features of the disclosure herein, where PLC may beimplemented, there may be a use of multiple frequency bands for PLC. Thecontrollers or the communication devices may choose a frequency bandwith a good SNR. This may help overcoming low SNR issues.

According to features of the disclosure herein, where PLC may beimplemented, a filter may be added to filter out the noise in thefrequencies used for PLC. This may improve the SNR.

Reference is now made to FIG. 1 , which illustrates an electricalnetwork 100 comprising input power source 101, electrical load 102,switch 103 (e.g. relay, IGBT, MOSFET), controller 105 and priority label104. Priority label 104 may be associated with load 102 or with switch103. Priority label 104 may be readable by controller 105. Power source101 may be a DC power source or an AC power source. Switch 103 may be“on” or “off” according to priority label 104. In order for load 102 towork properly, the power available from power source 101 should meet thepower demand from load 102. As long as the power demand from load 102may be maintained lower than or equal to the power available from powersource 101 the load may work properly. If the power available from powersource 101 may be smaller than the power demand from load 102, load 102might not work, or may work with deteriorated or impaired performance.

A controller (e.g. controller 105 of FIG. 1 ) may be realized ondifferent platforms, e.g. an analog circuit, microprocessor, DigitalSignal Processor (DSP), Field Programmable Gate Array (FPGA),Application Specific Integrated Circuit (ASIC) or other suitabledevices. In features where one of the power sources may be aphotovoltaic (PV) system comprising a power converter such as aninverter, a controller may be located in a power converter which may bea part of the PV system, or may be located in a different location inthe premises with communication to the power converter.

According to features of the disclosure herein, a controller may have amemory storing a software for managing the controller operations anduser interface, and it may be desirable to periodically update thesoftware of the controller (e.g. controller 105 discussed above, maincontroller 803 and/or controller 802 a of FIG. 8 , discussed below,and/or controller 501 of FIG. 5 , discussed below, etc.). The softwaremay operate the controller e.g. turning “on” and “off” switches, takemeasurements, send/receive information to other controllers, and/ormanage a graphical user interface (GUI) to interact with a user. Ifthere might not be a connection to an external network, a user mayupdate the software manually. In systems that include multiplecontrollers, including a main controller (discussed below in referenceto FIG. 4 ), the main controller may be connected the internet. Amanufacturer or the provider may remotely update the software of themain controller via the internet. Main controller may then send softwareupdates to other controllers via one or more communication lines (alsodiscussed below in reference to FIG. 4 ). According to features of thedisclosure herein, it may be possible to connect each of the controllersto the internet. In one scenario, connecting the controllers to theinternet may eliminate the need for a main controller, thus simplifyingthe system.

According to features of the disclosure herein, controller 105 may beequipped with sensors that enable it to measure total harmonicdistortion (THD) Controller 105 may be configured to disconnect switch103 if it detects high THD. The THD may be defined as the ratio of thesum of the powers of the harmonic components to the power of thefundamental frequency.

Controller 105 may control switch 103. It may set switch 103 to be “on,”i.e. allowing electrical current to flow from one terminal of switch 103to the other terminal, or it may set switch 103 to be “off,” i.e.blocking electrical current from flowing through switch 103. Controller105 may control switch 103 according the priority label 104. Prioritylabel 104 may be defined by a user according to the user preference, andit may be read by controller 105. Priority label 104 may be stored inthe memory of controller 105.

Reference is now made to FIG. 2 , which illustrates electrical network200. Electrical network 200 comprises power source(s) 201 a . . . 201 n,collectively referred to as “power sources 201,” load(s) 204 a . . . 204n, collectively referred to as “loads 204,” electrical connection(s) 202a . . . 202 n, collectively referred to as “electrical connections 202,”switches 203, controller(s) 205 and priority labels 206. Electricalnetwork 200 may receive power from power sources 201, and transfer thepower to loads 204 via electrical connections 202. Switches 203 may havethe capability of disconnecting and connecting one or more loads ofloads 204 from power sources 201. By disconnecting one or more loads ofloads 204 from power sources 201, the total power demand of loads 204may be reduced, thus potentially enabling other connected loads toreceive more power. For example, if the power generation capacity ofpower sources 201 is limited, and the power demand of the connectedloads of loads 204 may be above the limit, then disconnecting one ormore connected loads of loads 204 may lead to a smaller demand of power,such that the available power from power sources 201 may satisfy thedemand.

Disconnecting a load (e.g. load 204 a) from electrical network 200 maybe executed by changing the state of one or more switches of switches203. According to features of the disclosure herein, connecting anddisconnecting a load from an electrical network may involve changing thestate of one switch, or changing the state of more than one switch.Controller(s) 205 may set switches 203 to on/off positions in such a waythat the load may be disconnected from electrical network 200.

Controller(s) 205 may control the disconnecting and connecting of loads204 according to one or more rules or criteria. According to features ofthe disclosure herein, a priority-based rule may be used. For example, apriority label may be assigned to each load or group of loads. Accordingto features of the disclosure herein, each load receives its ownpriority label, and According to features of the disclosure herein, apriority label may be shared by multiple loads. Each load (orcorresponding switch) may then be managed according to the prioritylabel assigned to that load.

Assignment of priority labels may be variously implemented. According tofeatures of the disclosure herein, each load may include a readablememory device, with the load's priority label stored on the device.According to features of the disclosure herein, each load may furtherhave a communication circuit for communicating its priority label to acontroller. According to features of the disclosure herein,controller(s) 205 may have a memory device holding a lookup table, wherethe priority label of each connected load may be stored. Electricalconnections 202 a-202 n may link loads 204 to switches 203, such thatindividual loads may be connected and disconnected to power sources 201by switches 203.

According to features of the disclosure herein, two elements may becomparable. For example, two elements x and y may be comparable if theelements are of a set that is partially ordered by a binary relation ≤are comparable when either x≤y or y≤x.

Controller(s) 205 may control the switching of switches 203 according toa priority switching method. Priority switching may be based on one ormore variables. The variables may be defined as follows:

-   -   a_(i)=the i^(th) switch. The value of i may be between 1 and the        number of switches.    -   p(a_(i))=the priority label attributed to a    -   “on”=the electrical connections that may be controlled by the        switch are connected to one or more power sources.    -   “off”=the electrical connections that may be controlled by the        switch are disconnected from power sources.

Given that p(a_(i)) are comparable for every i, the following conditionmust be met under priority switching:

-   -   For every j and k, if p(a_(k))>p(a_(j)) then a_(k) may be        switched “off” only if a_(j) is switched “off”, and a_(j) may be        switched “on” only if a_(k) is switched “on”.

The direction of the inequality sign in the condition may be reversedaccording to the order of the priority labels (descending or ascending).For example according to the above condition, the switch or group ofswitches with the highest priority label may be switched “off” last, andthe switch or group of switches with the lowest priority label may beswitched “off” first. When reversing the direction of the inequality,the switch or group of switches with the highest priority label may beswitched “off” first, and the switch or group of switches with thelowest priority label may be switched “off” last.

According to features of the disclosure herein, the value of thepriority label may be stored in a memory device (e.g. non-volatile orvolatile memory, magnetic memory, read-only memory, flash, etc.) thatmay be a part of the controller or an external memory device that may beadded to the controller. A user or a software service may change thevalue of the priority by writing to the memory device the desired valuefor the priority label. In other features, wherein the user sets thepriority manually, the priority label may be stored in a physical switch(e.g. toggle switch, slide switch, rotary code switch, multi-polemulti-throw switch).

According to features of the disclosure herein, it may be desired tohave a dynamic priority label that matches the operation or currentstate of the load. For example, a PC monitor may be set to high prioritywhen on, and set to low priority when in standby mode. In a firstexample, this may be implemented using a smart load that may communicatewith a Smart Outlet and disclose information about its operation. In asecond example, this may be implemented using one or more methods forestimating the operation of the load.

According to features of the disclosure herein, the priority labels(e.g. priority labels 206 of FIG. 2 ) may belong to a set of two values.Referring again to FIG. 2 , the system illustrated comprises one or morepower sources 201 a-201 n, electrical loads 204 a-204 n, and anelectrical network of switches 203 that may connect power sources 201a-201 b to loads 204 a-204 n. Each switch of switches 203 may beassociated with a priority label of priority labels 206. Each prioritylabel of priority labels 206 may be assigned one of two possible values.These possible values may indicate a first priority or a second prioritylabel, wherein the first priority label is higher than the secondpriority label.

Controller(s) 205 may control switches 203 according to one or more ofthe total available power and energy from power sources 201, the powerdemand associated with loads 204, and the priority labels 206. Forexample, controller(s) 205 may regulate the power demand associated withconnected loads 204. In one scenario, the available power from powersources 201 may be 20 kW, and loads 204 may comprise eight (8) loads,wherein each load may require 3 kW. In this scenario, the total powerdemand of loads 204 is then 24 kW. The total power demand by loads 204(24 kW) is higher than the total power provided by power sources 201 (20kW). Controller(s) 205 may change the state of one or more switches ofswitches 203 such that one or more loads of loads 204 with the lowestpriorities may be disconnected from power sources 201. For example, load204 a and load 204 n may have the lowest priorities, and may bedisconnected from power sources 201. Assuming that load 204 a and load204 n each have a load of 3 kW, the total power demand after loads 204 aand 204 n are disconnected is 18 kW, which may be satisfied by powersources 201 (which has 20 kW of available power).

The systems for switching the switches by one or more controllers may bedone utilizing a variety of configurations. FIG. 3 a illustrates asystem 300 a using a centralized control method, wherein a singlecontroller 302 switches the switches 301 a . . . 301 n. That is,controller 302 may be used to switch each of switches 301 a . . . 301 nto an “on” position or to an “off” position. FIG. 3 b illustrates asystem 300 b that may use a decentralized control method, or adistributed method. Each group of switches (303 a . . . 303 m) has acorresponding controller 304 a . . . 304 n. Controllers 304 a-304 n maycommunicate in order to share information such as power measurements andpriority labels. In one example, multiple switches may be combined intoa single group, and one controller may control each of the switches inthe single group.

FIG. 4 illustrates a system 400 using a hybrid control method comprisingswitches 405 a-405 m collectively referred to as switches 405,controllers 406 a-406 n collectively referred to as controllers 406, andmain controller 407. Each controller of controllers 406 controls a groupof one or more switches of switches 405. Main controller 407 maycommunicate with and control controllers 406 via a centralized controlsystem. According to features of the disclosure herein, controllers 406may communicate with each other and bypass main controller 407.

Controllers (e.g. controllers 304 a-304 n, controllers 406 a-406 nand/or main controller 407) may communicate with each other usingvarious methodologies and technologies. According to features of thedisclosure herein, communication between a main controller (e.g. maincontroller 407) and other controllers (e.g. controllers 406 a-406 n) maybe simplex communication. In simplex communication, information may betransmitted only in one direction. For example, the main controller 407may only send information to the other controllers 406 but might notreceive information from controllers 406, or vice versa. According tofeatures of the disclosure herein, half-duplex or full-duplexcommunication may be used, wherein the controllers may bi-directionallytransmit and receive data to each other.

The communication between the controllers (e.g. controllers 406 a-406 nand/or main controller 407) may be over various mediums such aswireless, power lines, telephone or internet lines and dedicated lines,and also in a variety of communication protocols such as ZigBee™, ZigBeehome automation, Wi-Fi, Bluetooth™, x10, Ethernet, various cellularprotocols, PLC, or any other communication protocol that may be foundsuitable. For example, if the main controller 407 already has built-inWi-Fi, it may be advantageous to integrate Wi-Fi chips in the smartoutlets. In areas where connectivity may be unacceptable (e.g. the maincontroller 407 may be a part of a roof-mounted power converter, and somesmart outlets may be buried in the basement), or to increase reliablecommunication in some scenarios, PLC may be preferable.

According to features of the disclosure herein, a controller such asmain controller 407 of FIG. 4 or controller 604 of FIG. 6 maycommunicate with other controllers such as controller 406 a of FIG. 4 orsmart outlets such as smart outlet 602 a of FIG. 6 (discussed below) bymodulating a high frequency signal (e.g. at a frequency of 1 kHz, 10kHz, 100 kHz, 1 MHz or even higher) over the power lines. Power linescommunication (PLC) uses the existing wires for power as network cablesfor communication. For example the controller may use a frequencymodulation scheme such as frequency-shift keying (FSK) for transmittinginformation through frequency changes to the AC signal that may be usedto transmit power.

According to features of the disclosure herein, a signal may be also anabsence of a signal. For example, the communication device may expect toreceive a certain signal, and when not detecting such a signal thecommunication device can interpret this as a change, e.g. acommunication device may be configured to receive “ok” signals every 10seconds, if an “ok” signal is not received, the communication device mayreact as if a “not ok” signal was received.

According to features of the disclosure herein, a main controller, suchas main controller 407 of FIG. 4 , may be located at a utility powerprovider (e.g. a power plant). In this case, the utility power providermay use the main controller to control the power consumption of users byconnecting and disconnecting non-critical loads. Users may receivefinancial incentives in exchange for installing smart outlets that maybe disconnected by the utility power provider. For example, when theutility power provider might not keep up with the power demand (e.g.,the current load demand or anticipated load demand may be above athreshold, for example, the current or anticipated power production) itmay shift the frequency of the AC power produced by the utility powerplant. The shift may be by a small amount, for example up to %1 or up to%5 of the nominal frequency, in order to minimize disruption toconnected loads. The frequency shift may be detected by the smartoutlets which may disconnect according to the frequency shift. Whenthere may be excess power produced by the utility power plant, theutility power provider may again shift the frequency of the AC powerproduced by the utility power plant, and the smart outlets may detectionthe shift and responsively reconnect.

Alternatively, the main controller may be replaced by a centralized(e.g., “in the cloud”) software service. The measurements and thecontrol signal may be transmitted over the internet from and to thecontrollers. This feature may be robust during a power outage becausetelephone lines usually do not depend on the main grid.

Reference is now made to FIG. 5 , which portrays a smart outletaccording to illustrative features. Smart outlet 500 may be enclosed ina casing designed to be placed on any interior or exterior surface in apremises (e.g. a wall, ceiling, floor, table, countertop, etc.).Electrical connection 509 of smart outlet 500 may connect to powersources 507 via power lines that may be on or in the surface that smartoutlet 500 is be placed on. Smart outlet 500 may also be designed toconnect to existing electrical outlets in a premises by designingelectrical connection 509 as a power plug that may be plugged to theexisting electrical outlets. Smart outlet 500 may comprise controller501, switch 502, electrical connection 509 and electrical connection503. Controller 501 may be any of the controllers described herein, suchas those discussed above in reference to FIGS. 1, 2, 3 a, 3 b, 4 etc.Switch 502 may link electrical connection 503 to electrical connection509. Electrical connection 503 may provide a connection to load(s) 504,and electrical connection 509 may provide a connection to powersource(s) 507. Switch 502 may control the power transfer from powersource(s) 507 to load(s) 504. According to features of the disclosureherein, communication device 506 may be embedded in smart outlet 500,and according to features of the disclosure herein, communication device506 may be an external communication device that may be connected tosmart outlet 500.

Communication device 506 may be variously implemented. For example,communication device 506 may communicate over power lines, using PowerLine Communication (PLC) methods. According to features of thedisclosure herein, communication device 506 may comprise wirelesstransceivers, and may communicate using wireless technologies andprotocols, such as ZigBee™, Wi-Fi, Bluetooth™, and/or cellular networks.

The value of priority label 508 may be set manually by a user, setautomatically by a smart load communicating with smart outlet 500, orset automatically by controller 501. The value assigned to prioritylabel 508 may be set, reset and/or modified according to events in theelectrical network. The value of priority label 508 may be stored inmemory readable by controller 501 (e.g. in internal controller memory,or in an internal or external memory device coupled the controller), orin a state of a multi-throw switch that may be set by a user. Forexample, FIG. 5 a illustrates a rotary switch 511 with eight (8) states.Each state may represent a priority label 513 that may be passed tocontroller 512. Returning to FIG. 5 , communication device 506 mayreceive data indicating the power that may be being supplied by thepower source(s), the potential power that may be supplied by the powersource(s), the power demand of the smart outlets in a local electricnetwork, a preferred priority label for each load, and other relevantdata.

Still referring to FIG. 5 , controller 501 may be configured to detectthe type of load 504 or the operation being performed by load 504 byanalyzing the waveform of the current being drawn by load 504 (e.g.detecting a parameter such as current magnitude, harmonic content,frequency, etc.) or any other available telemetries. Controller 501 mayset priority label 508 for load 504 based on this analysis.

According to features of the disclosure herein, smart outlet 500 mayinclude a small energy storage device (e.g. a battery and/or acapacitor). If a load connected to smart outlet 500 has a high peakpower demand for short periods of time, this may reshape the powerdemand curve, and may reduce the peak demand. A storage device may actas a low pass filter, and as a result, signals comprising highfrequencies may be filtered by the storage device. If there is too muchpower produced by the power source, i.e. more than the load requires, itmay be stored as energy in the storage device. When the load requiresmore power than the power source is able to produce, it may get theextra power from the energy stored in the storage device. For example apower source that may produce up to 5 W supplies power for a load thatdoes not require any power in idle mode, and in active mode requires 10W for 1 second every 1 minute. While the load is in active mode, thestorage device may deliver the extra 5 W that the load requires, andwhile the load is in idle mode, the storage device may “recharge” bystoring the excess power produced by the power source.

Reference is now made to FIG. 6 , which shows premises 605, powersources 601 a-601 n, collectively referred to as power sources 601,smart outlets 602 a-602 n, collectively referred to as smart outlets602, distribution board 603, controller 604 and switching circuit 606.Power sources 601 connect via distribution board 603 to premises 605.Smart outlets 602 may be located inside or near premises 605, and may beconnected to distribution board 603 via switching circuit 606.Controller 604 may control switching circuit 606. Controller 604 may beany of the controllers described herein, such as those discussed abovein reference to FIGS. 1, 2, 3 a, 3 b, 3 c, and/or 5. Controller 604 maydisconnect the power from any smart outlet of smart outlets 602 byswitching off one or more switches in the switching circuit, thusdisconnecting outputs of distribution board 603 from one or more smartoutlets 602. Smart outlets 602 may be distributed in different parts ofpremises 605. Controller 604 may be located near or within distributionboard 603. Switching circuit 606 may be a device that links thedistribution board 603 to smart outlets 602.

Still referring to FIG. 6 , power source 601 a may be a main power grid,which may be able to provide a high amount of power, and 601 b may be apower source producing limited power, such as PV sources (e.g. PV cells,PV modules, PV shingles etc.), batteries, wind turbine, flywheels orother alternative power sources. If power source 601 b is a directcurrent (DC) power source, power source 601 b may be connected via adirect current to alternating current (DC-to-AC) converter to thedistribution board 603. In case of a power outage or power reduction inthe main power grid (power source 601 a), power source 601 b may supplyenough power to meet the power demand in premises 605. If power source601 b does not produce enough power to meet the power demand in premises605, controller 604 may regulate the power demand by disconnecting oneor more smart outlets of smart outlets 602 a-602 n, to obtain anoperating condition where the power demand is lower than the maximumpower that power source 601 b is able to supply.

Still referring to FIG. 6 , communication between various systemcomponents may be implemented in various ways. For example, if powersource 601 a is a main grid and the power is transported over an ACcurrent, communication between controller 604 and smart outlets 602a-602 n may be implemented using power line communication (PLC)protocols, or any other change in the power signal provided by powersource 601 a (e.g. changes in the amplitude or frequency) that may berecognized by smart outlets 602 a-602 n. For example, a utility grid mayprovide power to smart outlets 602 a-602 n as 50 Hz alternating currentwith a voltage of 240 Vrms. Smart outlets 602 may be configured todetect a temporary change in the frequency and/or voltage. For example,a smart outlet may be configured to respond (e.g. disconnect or connecta load) to power delivered at a frequency of 51 Hz for about 100 msec,and/or respond to power delivered at an amplitude of 250V for about 100msec.

Distribution board 603 may comprise one or more circuit breakers thatmay disconnect the electrical current when the current may be too high.This property of a circuit breaker may be used for safety (e.g. preventwires from overheating and/or stopping current when there may be a shortcircuit). According to features of the disclosure herein, switchingcircuit 606 may be integrated into distribution board 603 by replacingthe circuit breakers with smart circuit breakers that may be controlledby controller 604. FIG. 7 illustrates an example for a smart circuitbreaker 710 that may comprise circuit breaker 711 and a switch 712.Smart circuit breaker 710 links power grid 715 and household loads 714.Circuit breaker 711 provides the required safety and protectionproperties, and switch 712 provides the ability to disconnect power grid715 from loads 714 that may be connected to the smart circuit breaker710.

Returning to FIG. 6 , the communication between various systemcomponents may be used to transfer data between the different elements.For example, controller 604 may send commands to connect or disconnectswitches from switching circuit 606, send information to smart outlets602 about available power and/or priority updates. Smart outlets 602 maysend measurements to controller 604, share information among each otherfor different purposes such as sending and receiving power measurementsin order to calculate the current available power and consumed power,and/or share information regarding connected loads in order todynamically change the priority labels.

Reference is now made to FIG. 8 , which illustrates a system using atwo-priority control methodology according to illustrative features.System 800 comprises power sources 804, loads 805 a-805 n collectivelyreferred to as “loads 805,” switches 801 a-801 n, collectively referredto as “switches 801,” controllers 802 a-802 n, collectively referred toas “controllers 802,” main controller 803, an optional storage device806, and memory 807. Each switch or a group of switches of switches 801may be controlled via a corresponding controller of controllers 802.Each switch or a group of switches of switches 801 may have a firstpriority label or a second priority label. The value of the firstpriority label may indicate a higher priority than the value of thesecond priority label. The value of the priority labels may be stored ina memory such as memory 807. Each controller of controllers 802 and maincontroller 803 may have a memory of its own, or each controller mayshare one or more memories with one or more controllers. The powersupply to power demand ratio of the system 800 may be in one of twomodes. In a first mode, the power demand of loads 805 may be met by thepower supplied by power sources 804. In a second mode, the power demandof loads 805 might not be met by the power supplied by power sources804. When power sources 804 are able to supply enough power to loads805, switches 801 may be turned “on,” regardless of their prioritylabel. When power sources 804 might not supply enough power to loads805, the group of switches from switches 801 having an associatedcontroller with the second priority label may be disconnected, and thegroup of switches from switches 801 having associated controllers withthe first priority label may remain “on.” As a result, the power demandof the connected loads, which are a subset of loads 805, may be lessthan the total power demand of loads 805. By reducing the power demandof the total connected loads, there may be a greater chance that thepower demand may now be met by the power supplied by power sources 804.

In another example, there may be four modes of power supply for a systemthat includes two power sources. In a first mode, both the first sourceand the second source may be connected to the system loads. In a secondmode, the first power source may be connected to system loads (i.e. itmay be able to provide power to system loads) and the second powersource may be disconnected from system loads (i.e. it might not be ableto provide power to system loads). In a third mode, the first powersource may be disconnected from the system loads (i.e. it might not beable to provide power to system loads) and the second power source maybe connected to the system loads (i.e. it may be able to provide powerto system loads). In a fourth mode, both the first and second powersources may be disconnected from the system loads.

The first source may support nearly any power demand, and the secondpower source may provide limited output power. When both the first andsecond power sources are connected to the system loads, sufficient powermay be provided by these sources to the system. When the first powersource is connected and the second power source is disconnected,sufficient power may also be provided by these sources to the system.When both sources are disconnected the power demand might not be met, assufficient power might not be provided to the system. When the firstsource is disconnected and second source is connected, there may be twopossible scenarios related to the power provided by the second powersource. In one scenario, the power provided by the second power sourcemay be higher than the power demand, and in a second scenario the powerprovided by the second power source may be not higher than the powerdemand. If the power provided by the second power source is higher thanthe power demand, then sufficient power may be supplied by the secondpower source to the system. If the power provided by the second powersource is lower than the power demand of the connected loads, thensufficient power might not be supplied by the second power source to thesystem 800.

Additionally, when the first source is disconnected and second source isconnected, there may be two possible scenarios related to the energyprovided by the second power source. In one scenario, the energyprovided by the second power source may be higher than the energy demandof the system over a certain time interval. In a second scenario, theenergy provided by the second power source may be not higher than theenergy demand over a certain time interval (e.g. a source that involvesa power storage device). In the second scenario, there may be a desireto draw less power from the source until the first power source isconnected to the system.

In both of these instances (i.e. when the first source is disconnectedand second source is connected and where the power or the energyprovided by the second power source is not higher than the demand),there may be a need or desire to reduce the power demand bydisconnecting loads. This may be achieved by disconnecting one or moreloads. For example, as indicated in FIG. 8 , main controller 803 maysend a signal to controllers 802. The signal may indicate a change inthe mode of the system. In response to receiving the signal, eachcontroller of controllers 802 may disconnect one or more loads of loads805 from the system. In one example, each controller or switch mayexecute method 1050 of FIG. 10 (discussed below).

In some of the features, it may be desirable to measure the power demandand the power supplied within system 800. For example, smart outletsthat may include a measuring device for measuring voltage, currentand/or power (e.g. wattmeter, voltmeter, and ammeter) and providing themeasurements to an associated control device. According to features ofthe disclosure herein, (e.g. in systems having two power sources, whereone of the power sources may be the main power grid and the second powersource may be a limited power source), it might not be necessary tomeasure power supplied to the system. If the amount of power that may beprovided by the second power source may be known in advance, and theamount of power that may be provided by the second power source may beenough to support a subset of loads in the electrical network, it may besufficient to determine whether or not the main power grid is connectedto the system. This may be executed by detecting islanding. As notedabove, in one example, a system may have two power sources, where one ofthe power sources may be the main power grid and the second power sourcemay be a limited power source. When only the limited source is connectedit may be assumed that there may be a need to reduce power consumptionautomatically. If the main power grid is connected, the switches may be“on.” When the main power grid is disconnected (e.g., due to islanding),switches that have the second priority label may be disconnected. Thisability may be achieved by different ways in different systems,depending on the components that comprise the system. For example in aPV system, there may be a converter (e.g., a DC/AC inverter) connectedbetween the second power source (e.g. PV generators) and the first powersource (e.g. the grid). The converter may have the ability to detect thedisconnection of the main grid (e.g., the ability to detect islanding).Island detection may be performed using various methods, including:

-   -   Passive methods e.g. under/over voltage/frequency, rate of        change of frequency, Harmonics detection etc.    -   Active methods e.g. negative-sequence current injection,        Impedance measurement, slip mode frequency shift etc.    -   Utility-based methods (e.g. the use of signals sent through the        grid, transfer-trip method etc.).

In some scenarios, local utilities may require islanding detection as aprerequisite for connecting an alternative power source to the maingrid, also referred to as anti-islanding protection. This may involvethe inclusion of elements that have the ability to stop delivering powerto the main power grid, while maintaining the power supply to the localnetwork. This may be accomplished by adding a switch that disconnectsthe main power grid when there may be a power outage, and reconnects itwhen the power restores. It may be possible to take advantage of thisproperty of islanding detection that may be already implemented in thesystem for the feature illustrated in FIG. 6 .

Reference is now made to FIG. 9 a which shows a flow diagram of method950 for priority switching in an electrical network according toillustrative features. Method 950 may be carried out by any of the oneor more controllers referred to herein, such as controller(s) 205 orcontroller 302, and may be applied to any of the electrical systemreferred to herein, such as system 100, system 200, system 300 a, system300 b, etc. To simplify description of method 950, an assumption may bemade that initially (i.e. at step 900) the switches are turned “on.” Oneskilled in the art would be able to apply the method to an electricalsystem under different initial conditions. The variable p holds thevalue of the lowest priority label currently assigned to any of theload(s) connected to the power source. At step 900 the variable p is setto “0”, which may be assumed to be the lowest priority label currentlyassigned to load(s) connected to the power source in this illustrativefeature of method 950.

At step 901 the controller carrying out method 950 compares theavailable power from the power sources (shown as P_(s)) and the powerdemand of the loads (shown as P_(d)) of the electrical system. Thecontroller may receive one or more measurements of available power (e.g.power produced by a power source such as power source 201 of FIG. 2 )and current power demand of the loads (i.e. the amount of power requiredby a group of loads such as loads 204 a-204 n of FIG. 2 ) of theelectrical system. The measurements may be directly measured bysensors/sensor interfaces or devices included in the controller(s) (e.g.controller(s) 205 of FIG. 2 ), or may be provided to the controller(s)via one or more communication devices (e.g. communication device 506 ofFIG. 5 , discussed above). If it is determined, at step 901, that theavailable power might not meet the power demand (i.e. P_(d)>P_(s)), thecontroller carrying out method 950 advances to step 903. At step 903,the controller turns the switches that have a p priority label to “off.”At step 905, the value of p may be increased by 1, and then the methodreturns to step 901 to check if the power demand is less than theavailable power. If this is not sufficient (i.e. it may be determinedagain at step 901 in the next iteration that P_(d)>P_(s)), then themethod again may advance to step 903, wherein the switches with thepriority label that is equal to the new value of p (here, “1”) may beturned off. Method 950 may repeat this process until the power demand islow enough (i.e. less than the available power).

If, at step 901, it is determined that the power demand is less than theavailable power from the powers sources (i.e. P_(d)<P_(s)), the methodmay advance from step 901 to step 904. At step 904, the controller mayconnect switches with priority level p (here, “0”), to the powersources. The method may then proceed to step 905, where the controllermay reduce p by 1 at step 906, but not less than the minimum prioritylabel in the system. If the value of p is already the value of thelowest priority label in the system then p may stay the same.

Reference is now made to FIG. 9 b which shows a flow diagram of method960 for priority switching in an electrical network according toillustrative features. Method 960 may be carried out by any of the oneor more controllers referred to herein, such as controller(s) 205 and/orcontroller 302, and may be applied to any of the electrical systemreferred to herein, such as system 100, system 200, system 300 a, system300 b, etc. To simplify description of method 960, an assumption is madethat initially (i.e. at step 900) the switches are turned “on.” Oneskilled in the art would be able to apply the method to an electricalsystem under different initial conditions. The variable p holds thevalue of the lowest priority label currently assigned to any of theload(s) connected to the power source. At step 910 the variable p may beset to “0”, which is assumed to be the lowest priority label currentlyassigned to load(s) connected to the power source in this illustrativefeature of method 960.

At step 911, the controller carrying out method 960 may compare theavailable power from the power sources (shown as P_(s)) and the powerdemand of the loads (shown as P_(d)). The controller may receive one ormore measurements of available power (e.g. power produced by a powersource such as power source 201 of FIG. 2 ) and current power demand ofthe loads (i.e. the amount of power required by a group of loads such asloads 204 a-204 n of FIG. 2 ). The measurements may be directly measuredby sensors/sensor interfaces or by devices included in the controller(s)(e.g. controller(s) 205 of FIG. 2 ), or may be provided to thecontroller(s) via one or more communication devices (e.g. communicationdevice 506 of FIG. 5 , discussed below). If it is determined, at step911, that the available power might not meet the power demand (i.e.P_(d)>P_(s)), the controller carrying out method 960 advances to step913. At step 913, the controller turns the switches that have a ppriority label to “off.” At step 915, the value of p may be increased by1, and then the method may return to step 911 to check if the powerdemand is less than the available power. If this is not sufficient(e.g., it may be determined again at step 911 in the next iteration thatP_(d)>P_(s)), then the method again may advance to step 913, wherein theswitches with the priority label that is equal to the new value of p(here, “1”) may be turned off. Method 960 may repeat this process untilthe power demand is low enough (i.e. less than the available power).

If, at step 911, it is determined that the power demand is less than theavailable power from the powers sources (i.e. P_(d)<P_(s)), the methodmay advance from step 911 to step 912. At step 912, the controller maycheck if it is possible to connect switches with priority p withoutviolating the inequality P_(d)<P_(s) (wherein P_(d) represents the powerdemand of the loads and P_(s) represents the available power of thepower source). Stated differently, the controller may determine whetherconnecting the loads with priority p to the power source may result inthe amount of available power exceeding the power demand from the loads.If it is determined at step 912 that connecting the loads with priorityp to the power source may result in the amount of available powerexceeding the power demand from the loads, the controller implementingmethod 960 may return to step 911 to check if Pd<Ps again. If the resultof this comparison has changed from a previous iteration of the method,the change may indicate that there was a change in the power demand orthe power available, or both. If it is determined at step 912 thatconnecting the loads with priority p to the power source might notresult in the amount of available power exceeding the power demand fromthe loads, method 960 may proceed to step 914. At step 914, thecontroller may connect switches with priority level p (here, “0”), tothe power sources. The method may then proceed to step 916, where thecontroller may reduce p by 1, but not less than the minimum prioritylabel. If the value of p is already the value of the lowest prioritylabel then p may stay the same. Method 960 may then return to step 911,where the method 960 may be repeated for the next group of switches of(i.e. switches that have a priority of p−1).

Methods 950 and 960 (as described in FIG. 9 a and FIG. 9 b ) may each beuseful in the event where one or more power sources within a system mayproduce sufficient power, but the energy stored by the power source(i.e., the ability of the power source to provide power over time) mightnot be enough to support the production of sufficient power for a longperiod of time. In this case, there may be a need to reduce the energydemand, which may be done by reducing the power demand (i.e. bydisconnecting loads from the power source). For example, a power storagedevice such as a battery may be charged with 10 kWh and may serve as apower source for a load. If the power demand of the load connected tothe battery is 2 kW, the battery charge may last for 5 hours, but if thepower demand of the load is reduced to 1 kW, then the battery charge maylast for 10 hours.

Reference is now made to FIG. 10 , which presents an example method 1050for managing a power system having two power sources. One power sourceof these two power sources may be an alternative power source (e.g. a PVsource, storage device, windmill or other alternative power sources).The system may further comprise a plurality of smart outlets, such asthe smart outlet shown in FIG. 5 . A priority label set associated withthe plurality of smart outlets may have two elements, a first prioritylabel and a second priority label. The value of the first priority labelmay indicate a higher level of priority than the value of the secondpriority label. Method 1050 may be carried out by a system-controldevice, such as controller 302 of FIG. 3 a or main controller 803 ofFIG. 8 . In a system with a PV source, a converter within the system mayinclude the system-control device.

The system-control device may start method 1050 at step 1000, where thesystem-control device may determine if a main power grid is connected tothe smart outlets. In one example, the system-control device may makeuse of islanding-detection methods to determine if the main power gridis connected. If the controller determines at step 1000 that the mainpower grid is connected to the smart outlets, then the system-controldevice may advance to step 1001. At step 1001, the system-control devicemay broadcast a first signal. The first signal may broadcast a valuecorresponding to the value of the first priority label. This signal maybe received by smart outlets and may indicate to the smart outlets thatthe power sources may provide enough power to support the loads in thesystem. In response, smart outlets may carry out step 1115 of method1160 (described below) according to the received first signal. If it isdetermined at step 1000 that the main power grid is not connected, thenthe system-control device may proceed to step 1002, in which thesystem-control device may broadcast a second signal. The second signalmay broadcast a value corresponding to the value of the second prioritylabel. The second signal may be received by smart outlets and mayindicate to them that the power sources may support a subset of theloads in the system. In response, smart outlets may carry out step 1113of method 1160 (described below) according to the received secondsignal.

Reference is now made to FIG. 11 , which presents an example method 1160that may be executed by smart outlets within the system discussed abovein reference to FIG. 10 . Method 1050 and 1160 may be executedsimultaneously or near-simultaneously by the system-control device andthe Smart Outlets, respectively. Each smart outlet may be executingmethod 1160 independently, or there may be a main controller executingmethod 1160 for each smart outlet and passing the resultant commands tothe smart outlets. At step 1110, the Smart Outlets may be initialized to“ON.” At step 1111, each Smart Outlet may determine whether its priorityis set to the second priority label. If the Smart Outlet determines, atstep 1111, that its priority is not the value of the second prioritylabel, then no action may be taken and the method may loop back to step1111. The priority of the Smart Outlet is set to the value of the firstpriority label which indicates that the Smart Outlet may be “ON” in anyscenario, until the priority of the Smart Outlet is changed to the valueof the second priority label.

If the Smart Outlet determines, at step 1111, that its priority is thevalue of the second priority label, then the Smart Outlet proceeds tostep 1112. At step 1112, the Smart Outlet checks (e.g., by monitoring acommunication channel) whether a second signal is being broadcasted fromthe system-control device (at steps 1002 and 1001, discussed above inreference to FIG. 10 ). If a second signal is not being broadcasted,then the Smart Outlet proceeds to step 1114, where it determines if afirst signal is being broadcasted from the system-control device. If afirst signal is not detected at step 1114, then the Smart Outlet returnsto step 1111. If the Smart Outlet determines at step 1114 that thesignal coming from the system-control device is the first signal thenthe Smart Outlet may proceed to step 1115, where it may turn “ON.” TheSmart Outlet may then return to step 1111. If the Smart Outlet detectsthe second signal at step 1112, the Smart Outlet may proceed to step1113. At step 1113, a smart outlet that has the second priority labelmay be turned “OFF.” The Smart Outlet may then return to step 1111.

According to features of the disclosure herein, it may be desired todetect if a load is connected to an electrical connection. If the loadis not connected to an electrical connection, the electrical connectionmay be disregarded by an associated method such as method 1160 of FIG.11 or method 950 of FIG. 9 a to save computational time and memoryresources. Detecting if a load is connected may be done by measuring theimpedance at the output of the electrical connection, or by measuringthe power transferred from the electrical connection, or by measuringthe current through the electrical connection, or by a sensor that maymechanically detect that there is a plug in the socket (e.g. a springthat closes an electrical circuit, a proximity sensor etc.).

Reference is now made to FIG. 12 , which illustrates a method 1250 forswitching loads wherein two or more loads have the same priority label.A system-control device may start at step 1201 wherein the value of thevariable p may be set to the lowest priority label comprised byconnected loads. The system-control device may advance to step 1202wherein it may determine if the power provided by power sources (e.g.power sources 201 of FIG. 2 ) may meet the power demand of connectedloads (e.g. loads 204), shown as P_(d)<P_(s). If the power demand ishigher than the power provided (i.e. P_(d)>P_(s)), the system-controldevice may proceed to step 1203, wherein a load with priority label pmay be disconnected from the power source. The system-control device maythen proceed to step 1204, where it may determine if there may be anymore connected loads with priority label p. If there are additionalconnected loads with priority p, the system-control device may return tostep 1202. If there are no more loads with priority label p, then thesystem-control device may increase the value of p to the next highervalue at step 1205, and may return to step 1202.

If at step 1202 the power demand is lower than the power provided (i.e.P_(d)<P_(s)), the system-control device may proceed to step 1206,wherein it may connect a load with priority label p, and may advance tostep 1207. At step 1207, the system-control device may determine ifthere are any more disconnected loads with priority label p. If thereare additional disconnected loads with priority label p, thesystem-control device may return to step 1202. If there are no moredisconnected loads with priority label p, then the value of p may bereduced to the next lower value at step 1208, and the system-controldevice may return to step 1202.

Reference is now made to FIG. 13 , which illustrates a system forinter-controller communication according to illustrative features. FIG.13 comprises controllers 1301 a-1301 n, smart outlets 1302 a-1302 n andshared bus 1303 for communication. Controllers 1301 a-1301 n areassociated with smart outlets 1302-1302 n respectively. Shared bus 1303may be a dedicated wired bus or a shared memory for communicationbetween controllers 1301 a-1301 n. Communication between controllers1301 a-1301 n may be used to exchange information such as powermeasurements and priority labels or messages that may be transferred forwhen carrying out different methods such as method 950 of FIG. 9 a ormethod 1050 of FIG. 10 . The shared memory may also be used for savinginformation regarding the system, such as priority labels, power usagehistory and more. When shared bus 1303 is a shared memory or a dedicatedwire for communication, it may provide advantages when the controllersare located near each other. For example, it may be simple andeconomically efficient to connect the controllers and/or communicationdevices to one bus dedicated for communication, or to one shared memorywith read and write functions. Another example may be wirelesscommunication, using Wi-Fi, Bluetooth, LTE, or any other wirelessprotocol that fits the characteristics of the system.

Reference is now made to FIG. 14 , which illustrates system 1400, adirect wireless connection between the controllers. System 1400comprises controllers 1401 a, 1401 b, and 1401 c, collectively referredto as controllers 1401, smart outlets 1402 a, 1402 b, and 1402 c, andcommunication devices 1403 a, 1403 b, and 1403 c, collectively referredto as communication devices 1403. Each of the controllers 1401 andcorresponding communication devices 1403 may be associated with adifferent smart outlet. Controllers 1401 may use communication devices1403 to send and receive messages to/from other controllers.Communication devices 1403 may directly communicate with each otherusing wireless communication.

FIG. 15 illustrates system 1500, which includes wireless connectionsbetween controllers via an access point (AP) 1503. System 1500 comprisesAP 1503, controllers 1501 a, 1501 b, and 1501 c, collectively referredto as controllers 1501, and smart outlets 1502 a, 1502 b, and 1502 c.Each of controllers 1501 may be associated with a different smartoutlet. Each controller of controllers 1501 may comprise a communicationdevice for sending and receiving information. Controllers 1501 maycommunicate with each other via AP 1503 that may serve as a router formessages between controllers 1501. According to features of thedisclosure herein, AP 1503 may be integrated in a part of theinstallment of the system (e.g. integrated in a main controller such asmain controller 803 of FIG. 8 , or integrated in a converter which maybe part of power source 601 b of FIG. 6 ). According to features of thedisclosure herein, AP 1503 may be a previously deployed AP (e.g. astandard home Wi-Fi™ router).

According to features of the disclosure herein, a controller (e.g.controller(s) 205 of FIG. 2 ) may consider a multi-objective functioncomprising the priority switching and the utilization of the powerprovided by power sources (e.g. power sources 201), wherein thecontroller may try to satisfy both the priority switching, (i.e.disconnecting low priority loads before higher priority loads), andkeeping the power demand as close as possible to the power provided bythe power sources. In one example, the power provided by the powersources in a system may be 10 kW. There may be two loads in the system,wherein the first load requires 15 kW and has a high priority label, andthe second load requires 1 kW and has a low priority label. According topriority switching that was defined previously, if a priority label of afirst load is higher than a priority label of a second load, then thefirst load may be switched “off” if the second load is switched “off”,and the second load may be switched “on” if the first load is switched“on”. This may result in zero utilization of the power provided by thepower sources. A controller using a multi-objective function mayreconnect the low priority load subsequent to disconnecting the highpriority load, thus realizing a better utilization of the power providedby the power sources. This may be achieved by adopting an algorithm forsolving the knapsack problem (KP). The KP may be described by thefollowing description: given a set of items, each item having a weightand a value, determine a subset of items to include in a collection suchthat the total weight is less than or equal to a given limit and thetotal value is maximal. According to features of the disclosure herein,each item may represent a load, its weight may be its power demand andits value may be its priority label value or a function of its prioritylabel. Although this method maximizes the utilization, it may violatethe priority switching definition.

According to features of the disclosure herein, a controller may turn“on” or “off” loads, and according to features of the disclosure herein,a controller may use more options that involve turning the load “on” butlimiting the amount of power that it may draw. For example a 100 W lampthat may be limited by a controller to draw only 80 watts may produceless light but may still function as a light source. A second examplemay be an AC unit that may be limited to cool a room down to a certaintemperature (e.g. 75 degrees Fahrenheit) this may limit the amount ofpower the AC unit requires for cooling the room.

According to features of the disclosure herein, an electrical networkmay be connected to multiple power sources, one of which may be theoptional storage device 806 of FIG. 8 . A storage device may be one ormore batteries, storage capacitors and/or flywheels. During times wherethe power provided by the power sources (excluding the storage device)is larger than the power required by the loads, the storage device maybe charged with the extra power. During times where the power providedby the power sources excluding the storage device is less than the powerrequired by the loads, the storage device may provide additional powerby discharging energy. If one of the other power sources in the systemis a photovoltaic (PV) system, the storage device may be charged duringday time (when there may be a lot of sunlight), and during nighttime,(when the PV system may provide less power), the storage device mayprovide the power by discharging energy. The information about the powersources in the electrical network may help to predict the likelyavailable power profile. The likely available power profile may help thecontroller to predict the available power for the loads in theelectrical network and decide what loads to turn off, turn on, or limitthe amount of power the loads may draw.

For example, a premises may have two power sources (one of which may bea storage device) and only two loads, a medical ventilator machine witha high priority label and an air conditioning unit (A/C unit) with alower priority label. Even when the two power sources generate enoughpower to support both loads, the controller may decide to turn the lowpriority load off or to limit the power supplied to the low priorityloaded because the likely available power profile may indicate thatthere may be limited power soon that might not be enough for any of theloads. By limiting the power supplied to the A/C unit power, the storagedevice may be charged. Subsequently, at a later point, when there isinsufficient power provided by the other power sources, the storagedevice may provide the extra power needed to keep the medical ventilatormachine turned on.

According to features of the disclosure herein, it may be useful topredict the likely available power profile. A likely available powerprofile may be predicted according to different parameters depending onthe power sources that may be connected to the system. One method ofacquiring the information may be receiving one or more related manualinputs from a user through a user interface. For example, to predict thepower that may be produced by a PV system, it may be useful to know thelocation of the system. This may be because of the geographic conditionsin which a PV system may be installed in and may determine the amount ofpower produced by the PV system (e.g. a PV system may produce less powerin Greenland than an identical or similar system in Egypt). Anothermethod of acquiring the information may include installing relevantsensors that may have the ability to provide the information. Forexample, instead of receiving a manual input from a user indicating thecountry in which a PV system is located in, a GPS (or any othersatellite navigation system) sensor may provide this information.Additional information may be provided from a connection to theinternet, such as weather and cloud cover. A controller that receives aweather forecast of significant cloud cover may change its prediction ofthe likely available power profile.

The likely available power profile may also be predicated by collectingmeasurements of the power profile history. Some methods may provide goodpredictions based on information from the past. In some scenarios,filter predictors such as linear predictor, moving average (M.A.)predictor, and autoregressive (A.R.) predictor may be sufficient, and inother scenarios some more complex methods that involve machine learningmay be implemented. According to features of the disclosure herein,information may be shared between different premises to improve theprediction. Sharing information between different premises may providecertain advantages, some may be reducing measurement errors andcompensate defective sensors.

FIG. 16 illustrates system 1600 which may be an example of using sharedinformation between premises that include a storage device to improveprediction. System 1600 comprises premises 1601, 1602, and 1603, sun1604, cloud 1605 and wind 1606. Each premises may have a storage device(such as a battery) and a PV system. Initially premises 1601 may beshaded by cloud 1605, so the controller of premises 1601 may notify thecontroller of premises 1602 and the controller of premises 1603 thatpremises 1601 is shaded. Subsequently, wind 1606 may cause cloud 1605 tomove to the right, thereby causing premises 1602 to be shaded by cloud1605. The controller of premises 1602 may notify the controller ofpremises 1601 and the controller of premises 1603 that premises 1602 isnow shaded. Based on this information, the controller of premises 1603may predict that it will be shaded soon, so the controller of premises1603 may save power by disconnecting low priority loads, and charge itsstorage device with the saved power. Subsequently, when wind 1606 movescloud 1605, causing it to shade premises 1603, premises 1603 may providepower for high priority loads from the storage device. It is understoodthat one of ordinary skill in the art may slightly modify methodsdisclosed herein by using different filters (M.A., A.R. etc.). Suchmodified methods are within the scope of the feature disclosed herein.

Another power profile that may be predicted may be the profile of thepower required by loads in systems such as system 800 of FIG. 8 .Predicting the amount of power that may be required by loads in thefuture may affect how much power may be used in the present, and howmuch power may be stored in a storage device for times when there mightnot be enough power provided by the power sources. Prediction of powerthat may be required by loads in the future may include analysis ofvarious factors, such as time of day, day of week or month, season,temperature, historical measurements of power required by loads, etc.These factors may affect the amount of available sunlight and/or theamount of power provided and/or the amount of power demand of the loads.

Reference is now made to FIG. 17 , which illustrates a dual AC-DC systemcomprising PV generators 1701, PV power devices 1702, converter 1703,main power grid 1704, storage device 1713, dual distribution board 1710(comprising DC distribution board 1705 and AC distribution board 1706),DC smart outlets 1711 a and 1711 b (collectively referred to as “DCsmart outlets 1711”), AC smart outlets 1712 a and 1712 b (collectivelyreferred to as “AC smart outlets 1712”), DC loads 1708 a and 1708 b(collectively referred to as “DC loads 1708”), and AC load 1709 a. PVgenerators 1701 generate DC power that may be transmitted to PV powerdevices 1702. PV power devices 1702, which may comprise one or moreDC-DC converters and may comprise a monitoring device, transfer thepower to DC smart outlets 1711 via DC distribution board 1705, and toconverter 1703. Any surplus power from PV power devices 1702 may bestored in storage device 1713. Converter 1703 transfers the powerreceived from PV power devices 1702 to AC distribution board 1706. ACdistribution board receives power from both PV power devices 1702 andmain power grid 1704, and transfers the power to AC smart outlets 1712.Converter 1703 may communicate with PV power devices 1702 in order tocontrol the increasing or decreasing of the power drawn from PVgenerators 1701, e.g. tracking the maximum power point (MPPT) on thepower curve of PV generators 1701 or selecting a different power pointto match a signal such as an electrical parameter (e.g. current, voltageand/or temperature), and also may communicate with the smart outlets1711 and 1712 and/or a smart distribution board which may be installedinstead of distribution boards 1705 and 1706. Each smart outlet may beconnected to either DC power (received DC distribution board 1705) or ACpower (received from AC distribution board 1706). DC only or AC onlysmart outlets may be realized as illustrated in FIG. 5 .

FIG. 18 illustrates system 1800 b, which may be a dual AC-DC system. Thesystem 1800 b comprises PV generators 1801, PV power devices 1802,converter 1803, storage device 1813, main power grid 1804, dualdistribution board 1810 (comprising DC distribution board 1805 and ACdistribution board 1806), dual smart outlets 1807 a, 1807 b, and 1807 c(collectively referred to as “dual smart outlets 1807”), DC load 1808 aand 1808 b, and AC load 1809 a and 1809 b. Each dual smart outlet of thedual smart outlets 1807 may be connected to both AC and DC power lines,and may provide power to both DC loads and AC loads. An example for adual smart outlet is illustrated in FIG. 19 .

Reference is now made to FIG. 19 , which illustrates a dual AC-DC smartoutlet. The illustrated system comprises DC power sources 1901, AC powersources 1906, DC load 1905, AC load 1909, communication device 1911,priority label 1912 and dual smart outlet 1900. Dual smart outlet 1900may comprise controller 1910, electrical connection to AC power sources1906, electrical connection to AC load 1908, switch 1907, electricalconnection to DC power sources 1901, electrical connection to DC load1905, and switch 1903. Switch 1903 together with connections 1902 and1904 may provide a link between DC load 1905 and DC power sources 1901.Switch 1907 together with connections 1913 and 1908 may provide a linkbetween AC load 1909 and AC power sources 1906. Switches 1903 and 1907may be controlled by controller 1910. Controller 1910 may set the stateof switches 1903 and 1907 according to priority label 1912 and accordingto data that may be received from communication device 1911. Controller1910 may also transmit data regarding the state of switches 1903 and1907, and data regarding the power provided by power sources 1901 and1906 and the power required by loads 1905 and 1909. According tofeatures of the disclosure herein, controller 1910 may also communicatewith a smart load (i.e. a load that has a communication deviceconfigured to communicate with controller 1910).

Some features may include a Graphical User Interface (GUI) formonitoring and/or controlling an associated electrical system. Accordingto features of the disclosure herein, the GUI may be displayed on amonitor on or near the distribution board, or any other place chosen bythe installer. According to features of the disclosure herein, the GUImay be displayed on a PC (e.g. a web application), phone or tablet (e.g.iOS or Android apps). The GUI may be further extended to be able tohandle user input (e.g. setting the priority label for each switch, orconnecting/disconnecting loads via a mobile app).

Further features may include user interfaces for monitoring loaddivision in some power systems. A system owner or operator may be ableto view a list of power sources, loads, and priority labels with amapping between each load and the priority labels, and may also viewinformation regarding the power supply from the power sources or eachpower source and the power demand from the loads or each load. Accordingto features of the disclosure herein, the list may be a graphical userinterface (GUI) viewable on a computing device, such as a computermonitor, tablet, smart-television, smartphone, or the like. According tofeatures of the disclosure herein, the system operator may be able tomanually set the priority label of the loads through the GUI (e.g. bypressing buttons).

Reference is now made to FIG. 20 a which illustrates an example of apage in a GUI application for a touchscreen device such as a tablet,smartphone etc. The page shown in FIG. 20 a displays the list of loadsin an electrical network. By clicking on a device name on the page amenu may open or the page may change and display the properties thatrelate to the specific load including the priority label of the load.The user may change the properties of the loads which may includeoptions for setting timers for temporary changes or future changes. Ondifferent pages of the application the user may monitor the storagedevice charge status, the amount of power that may be generated by PVgenerators (if there are any in the system), the amount of power thatmay be consumed by the loads, charts and graphs of past data that wascollected previously, charts and graphs of the power supply and demand,power supply and demand prediction etc.

The application may display a page that includes a graphical userinterface. The page comprises notification bar 2001, return button 2002(that when pressed, displays on the screen the previous page), title2003 (which displays the title of the page), buttons 2004 and 2006 forswitching between other pages in the application, an icon 2005 for thecurrent page, load 2011 (the name of a load that may be controlled by aswitch e.g. load 504 and switch 502 of FIG. 5 ), box 2008 (comprisingload 2011 on the left and button 2009 on the right). The backgroundcolor of box 2008 may be set according to the priority label of load2011, such as priority labels 508 and load 504 of FIG. 5 . In oneexample, higher priority labels may result in a brighter coloredbackground. Button 2009 may show the current state of the switch thatcontrols load 2011, such as switch 502 of FIG. 5 . In one instance,pressing of the button 2009 may toggle the state of the switch. When box2008 is pressed, the page may switch to a page that lists properties ofload 2011. An example of a page that lists properties of a load isillustrated in FIG. 20 b . The page that displays properties of thechosen load in FIG. 20 b allows a user to edit according to the userpreference one or more properties of the load (e.g. the load name, thepriority label associated with the load, the power demand of the loadmay be displayed numerically or in a graph where the power demand may beplotted over time interval selected by the user (day, week, month oryear)). For example, the page shown in FIG. 20 b may include one or morecontrols that allow a user to edit one or more properties of the load.

Reference is now made to FIG. 21 a which illustrates a dual AC-DC smartoutlet 2110 such as Dual Smart Outlet 1807 a of FIG. 18 . The smartoutlet comprises three different connections to loads: two ACconnections 2101 and 2103 and a single DC connection 2102 configured toconnect to a male USB type “A” connector. Similarly FIG. 21 billustrates a dual AC-DC smart outlet 2120 such as Dual Smart Outlet1807 a of FIG. 18 , wherein the smart outlet comprises two connectionsto loads: a single AC connection 2105 and a single DC connection 2104configured to connect to a male DC connector. The DC connectors in FIG.21 a and FIG. 21 b may be replaced by any other DC connector.

Reference is now made to FIG. 22 which illustrates a dual AC-DC smartoutlet (such as Dual Smart Outlet 1807 a of FIG. 18 ) comprising aconnection to a DC load and/or a DC load. The connection comprises twoparts: an AC connection comprising 3 connections: neutral 2201, live2202 and ground 2203, and a DC connection comprising two connections: DCpositive 2204 terminal and DC negative terminal 2205. The smart outletcomprises a single connection to a load, configured to connect to a dualAC-DC plug 2206, an AC plug, or a DC plug. The DC part of the connectionto a load may be designed to connect to a common coaxial powerconnector, or to any other DC connection that may be consistent for boththe plug and the socket.

It is noted that various connections are set forth between elementsherein. These connections are described in general and, unless specifiedotherwise, may be direct or indirect; this specification is not intendedto be limiting in this respect. Further, elements of one aspect of thedisclosure may be combined with elements from other aspects inappropriate combinations or subcombinations. For example, the system forinter-controller communication illustrated in FIG. 13 may be combinedwith the electrical network of FIG. 8 and/or the control methods ofFIGS. 3 b and 4. As another example, the rotary switch of FIG. 5 a maybe used to set the priority of smart outlets 602 a-602 n of FIG. 6and/or of smart outlets 1402 a-1402 c of FIG. 14 . These examples arefor illustrative purposes and are non-limiting (i.e., other combinationsmay be made).

What is claimed is:
 1. A method comprising: measuring power provided bya power source; measuring a power demand of one or more loads receivingpower from the power source via one or more smart outlets; comparing themeasured power provided by the power source and the power demand of theone or more loads; and signaling, in response to a determination thatthe power demand of the one or more loads is greater than a firstthreshold, a first smart outlet of the one or more smart outlets byaltering at least one of magnitude and frequency of a providedalternating-current power supply, wherein, based on the signaling, aswitch associated with the first smart outlet is controlled todisconnect a first load of the one or more loads, wherein the switchcomprises a first electrical connection and a second electricalconnection, wherein first electrical connection, the second electricalconnection, and the switch are enclosed in a casing designed to bemounted on or in a surface in a premises, and wherein the secondelectrical connection is connected to the power source using power linesthat are on or in the surface.
 2. The method of claim 1, wherein thepower source is a photovoltaic power source.
 3. The method of claim 1,wherein the power source is a utility grid.
 4. The method of claim 1,wherein signaling is carried out by power line communication.
 5. Themethod of claim 1, wherein the switch is further controlled based on afirst priority label associated with the first load.
 6. The method ofclaim 1, further comprising assigning one or more priority labels to oneor more of the one or more loads; and wherein disconnecting one or moreof the one or more loads is done according to the one or more prioritylabels.
 7. The method of claim 1, further comprising: measuring thepower provided by the power source, measuring the power demand of theloads of the one or more loads still receiving power from the powersource; and signaling, in response to a determination that one or moreof the disconnected loads can be reconnected without the power demandexceeding a second threshold, one or more smart outlets to reconnect oneor more of the disconnected loads.
 8. The method of claim 1, furthercomprising measuring at least one of current or voltage by the smartoutlet.
 9. The method of claim 1, wherein the first smart outlet iscontrolled by a controller integrated into an electrical distributionboard.
 10. The method of claim 9, wherein the electrical distributionboard comprises one of an alternating current (AC) electricaldistribution board or a direct current (DC) electrical distributionboard.
 11. The method of claim 9, wherein the controller and the switchare located next to a distribution board controlling electrical power toa premises.
 12. An apparatus comprising: a first electrical connectionconfigured to connect to one or more loads; a second electricalconnection configured to connect to one or more power sources via apower line; a first communication device configured to communicate viathe power line; a first switch linking the first electrical connectionand the second electrical connection; and wherein the first switch isconfigured to be controlled via the first communication device byaltering at least one of magnitude and frequency of a providedalternating-current power supply via the power line and, responsive tosaid controlling, to disconnect a first load of the one or more loads,wherein the first electrical connection, the second electricalconnection, the first switch, and the first communication device areenclosed in a casing designed to be mounted on or in a surface in apremises, and wherein the second electrical connection is connected topower lines that are on or in the surfaces.
 13. The apparatus of claim12, further comprising a controller configured to control the firstswitch based on a first priority label associated with the first load.14. The apparatus of claim 13, wherein the controller is configured tomeasure a power demand associated with the one or more loads.
 15. Theapparatus of claim 13 wherein the controller is configured to receiveinformation from a main controller, process the information with regardto the first priority label, and control the first switch.
 16. Theapparatus of claim 13, wherein a value of the first priority label isconfigured to change dynamically based on an operating state of the oneor more loads.
 17. The apparatus of claim 12, wherein the firstcommunication device and the first switch are placed next to adistribution board controlling electrical power to a premises, and thefirst electrical connection is located on a surface in the premises. 18.The apparatus of claim 12, wherein the first communication device isconfigured to communicate by power line communication (PLC).
 19. Theapparatus of claim 12, further comprising a measuring device formeasuring at least one of voltage, current, or power of the of theprovided alternating-current power supply.
 20. The apparatus of claim12, wherein the apparatus is integrated into an electrical distributionboard.